Electric clock



F. C. HOLTZ ELECTRIC CLOCK Filed Nov. l5J 1924 Feb. 14, 1928.

Patented Feb. 14., 1928.

UNITED STATES PATENT OFFICE.

FREDERICK C. HOL'IZ, 0F SPRINGFIELD, ILLINOIS, ASSIGNOR T O. SANGAMO ELECTRIC COMPANY, F SPRINGFIELD, ILLINOIS, A CORPORATION 0F ELECTRIC CLOCK'.

Application filed November 15, 1924.- Serial No. 750,208.

. My invention relates to clocks,and particularly to clocks in which in lieu of the usual main spring an electric motor is employedas the source of power for driving the time train. It has for its objects to obtain the maximum in simplicityv of construction whereby liability to derangement is reduced to a minimum; to provide improved means for driving the time train of the clock such afs t0 render it practicable to reta-in, as far as possible, the highly7 developed 'construction of a modern clock movement, and with but slight alteration to drivethe same electrically, whereby it will require but l1ttle Aor no attention for long periods of time; and, b esides, to so design the mechanism that it will be compact; that a constant driving ttorque will be exerted, thereby greatly improving the time keeping qualities of the clock, and l0 that all electrical contact devices will be eliminated and the electrical energy consumption be reduced to a minimum. I ace complish these objects as illustrated in the drawings and ashereinafter described.

z5 What I regard as new is set forth in the.

claims.

In the accompanying drawings,- Fig. 1 is a top or plan view of my improved clock, the case being omitted;l f Fig. 2 is a side view, partly in vertical section on line 2--2 of Fig.' 1;

Fig. 3 is a modified perspective view illustrating the relative arrangement of the clock movement and the driving mechanismtherefor, some parts being omitted for the sake of clearness;

Fig. 4 is a side view of the rotor element of thev motor by which theclock is driven,

some parts beingin section; and

` Fig. 5 is a cross-section on line 5-5of Fig. 4. l

Referring to the drawings,-6 indicates generally a clock movement `of any suitable description, but having no main springfor furnishing driving power. It is, however -provided with the usual'balance wheel 7 land regulator 8. as shown in Fig. 8, and .with a dial 9 and hour and'minute hands 10, 11. The clock movement 6 is preferably mounted l0 `between pillar plates 12, 13, as shown in Figs. 1 and 2, and is housed in a suitable case which encloses all the operating parts.

For driving the time train of the clock,I provide a small induction motor, the stator of which comprises a single phase bipolar laminated field magnet, indicated as a whole by the reference numeral 14, on which is mounted a coil 15 which constitutes the primary winding of the motor and is to be connected through its terminals 15, 15b to an alternating source of current supply. The poles 16, 17 of the field magnet 14 have their opposite faces curved so that a cylindrical opening is provided between them in which is rotatably mounted the armature or rotor 18 of the motor. Said rotor comprises a magnetic core member'made up of a plurality of laminations 19, and a squirrel cage winding thereon consisting of bars 20 and end plates 21, 22, which plates serve as end rings for the squirrel cage. The squirrel cage is 4preferably made of copper, and, as best shown in Fig. 4, the bars 20 are 0bliquely disposed, the latter arrangement being employed to give uniform starting torque, and thereby avoid a pulsating effect on the balance wheel spring. The ends of the bars 20 are preferably upset after the parts of the"`rotor are assembled, as illustrated inlFig. 4, so that they serve to securely hold the laminations together. While I prefer 'to use alaminated rotor, it is not essential that it be laminated, as a solid structure for many purposes will function equally well.

The rotor is mounted on a suitable shaft- 28 to rotate therewith, said shaft being also provided with a pinion 24, and with pivot pins25, 26 at its ends by means of which it maybe rotatably supported in the manner hereinafter described. i

As shown inFigs. 1 and '3, the field. magnet poleslrl'?v are provided with shading v coils 27 28 mounted on the pole tips in the manner well known to those familiar-with the art, which shading coils serve to change the pulsating flux of the field intoA a so-called shifting or substantially rotating magnetic field in the cylindrical space between the opposite poles of the field magnet.

As best shown in Fig. 1, the field magnet 14 -is mounted between two inverted U- shaped' yokes 29',l 30, the intermediate portions of which are bent outwardly to accom- .modate vthe shading coils 27, 28. In the intermediate portion of the yoke 29 is mounted a bearing plug. 31 fitted in a thread- 'ed opening so that it maybe adjusted endyoke 30 and' bracket wise. Said plug is provided at its innerend with a socket to receive the pivot pin 26 of the rotor shaft 23, as best shownv in Fig. 2. A lock'nut 32 screwed upon the inner end of said bearing plug holds it securely in its different positions of adjustment. As shown in F ig. 2, the intermediate portion of the yoke 30 is provided with an opening 33 large enough to permit of the free passage therethrough of the pinion 24, and the pivot pin 25 of the rotor shaft 23 is ittedin a suitable bearing in a U-shaped bracket 34 which is secured by screws 35 to the yoke 30, as best shown in Fig; 1. The intermediate portion of said bracket preferably lies close to the pillar plate 13, as shown in Fig. l, but is not connected therewith. Extending between the intermediate portions of the 34, and journaled in suitable bearings in said .1nembers, is a staff 36 which carries agcar 37 meshing with the pinion 24. Said staif also carries a pinion 38 which forms a driving connection with the clock movement, as will be hereinafter explained.

The motor and the connection above described are supported upon the pillar by means of a bracket 39 which is firmly secured to the field magnet 14 by screws 40 which pass through one end portion of the yokes 29, 30 and screw into the bracket 39, thereby binding said parts tightly together. 'The bracket 39 is in turn secured by screws 41 to a lug 42 carried by the pillar plate 13, as shown in Fig. 1.

The clock movement is driven from the motor through the pinion 38, which meshes with a gear 43 carried by a staff 44 that' extends through the pillar plate 13 Vand carries a pinion 45 that connects with the time train of the clock in any way suitable to impart to the clock mechanism the torque necessary to keep the balance staff, or the pendulum, in a constant state of oscillation. As the specific manner in which this is accomplished has nothing to do with my in- Avention I have not thought it necessary to illustrate any special arrangement for that purpose. The opposite end of the staif 44 is journaled in a suitable bearing in an angle bracket 46 secured to the pillar plate 13 by a screw 47, as shown in Fig. 2. The position of these parts is such that the gear 43 is always held properly in mesh with the pinion 38, but obviously the motor with the connections carried by the frame parts thereof, comprising the yokes l29,v 30 and brackets 34, 39may be removed as a unit without disturbing the gear 43, by simply removing .the screws 4l.

From the foregoing description it Will be understood that when current 1s supplied to the motor the rotation of the rotor shaft 23 will be transmitted throu h'the. speed reducing gearing comprising t e p1n10n 24,

said motor,

and in said bracket, a spur gear on said meshing with the pinion on said motor shaft,

gear 37, pinion 38, and gear .43 to the staff 44 through which the time train of the clock is driven, `and consequently such time train will be set in motion. The speed reducing gearing between the rotor shaft and the clock mechanism is preferably so designed that the desired torque will be imparted t0 the staff 44 with the motor armature revolving 'at a comparatively low speed. IVhilc I have shown and described the usev of a small alternating current motor, it will be quite evident to those skilled in the art that a small under similar principles could be used and comes within the scope of my invention.

Many advantages are realized by my improved construction, amongr the most important of which are the omission ofthe main spring with consequentrelief from the necessity of winding the clock; freedom from Inechanical difficulties and troubles owing to the fact that there are no contactsy and there is nothing to get out of order; the elimination of noise, and freedom from the necessity of lubrication, since the rotating parts move so slowly that they wear indefinitely. Tlie motor described may be attached to any suitable source of alternating current circuit from a conveniently located fixture or socket, and as long as the current supply is maintained the clock will operate without its being given any attention.

What I claim as my invention and desire to secure by Letters Patent, is-.

1. In an electric .driving device for clocks, the combination of an electric motor having an extending motor shaft, a U-shaped bracket projecting from said motor and having a ing-end of said motor shaft, a pinion on said motor shaft, a staif journaled in said bracket', a spur gear on said stati' meshing with said pinion, and a pinion on said staff adapt- .ed to transmit a slow speed drive to the clock. .a

2. In an electric driving device for clocks, the combinatin of an electric motor having an extending motor shaft, a yoke secured to a U-shaped bracket extendino' outwardly from the side of said motor and having a bearing at its end for receiving the extending end of said motor shaft, a lnion on said shaft, a stattl journaled in sai yok sta and a pinion on said staff adapted to transmit a slow speed drive to the clock.

' 3. In an electric driving device for clocks, the combination of an electric motor comprising a bipolar iield magnet, and a rotor mounted to Irotate between the poles thereof, a shaft for said rotor; a pair of yokes secured to. opposite sides porting one end of said rotor shaft, a.

of said field magnet, bearing means in one of said yokes for sugdirect current motor operating A bearing at its end for receiving the eXtendshaped vbracket extending laterally from v said pinion, and a pinion on said stai adapt ed to transmit a slow speed drive to the clock.

4. In an electric driving device for clocks, the combination of an electric motor comprising a bipolar eld magnet and a rotor mounted to rotate between the poles thereof, a shaft for said rotor, a pair of yokes secured to opposite sides of said field magnet, a bearing plug screwing into a threaded opening 1n one of said yokes and receiving one end of said rotor shaft, a U-shaped bracket extending laterally from said motor, the other end of said rotor shaft being journaled in the end of said bracket, a pinion on said rotor shaft, a staff journaled at one end in the end of said bracket and at the other end in the adjacent yoke, a spur gear on said staff meshing with said pinion,

and a pinion on said stati adapted to transmit a driving rotation to the` clock.

5. The combination with clock mechanism comprising pillar plates, a clock movement mounted between said pillar plates and a drive statt connected therewith, of an electric driving unit for said clock mechanism comprising an induction motor permanently connected to its source of current supply, bracket means for detachably mounting sald unit directly in rear of said pillar plates, said induction motor comprising a rotor shaft extending forwardly toward said clock mechanism, a bearing bracket extending from said motor towards said clock mechanism and atording a bearing support vfor the end of said rotor shaft, a pinion on said shaft, a stati extending substantially parallel with said rotor shaft and journaled in said bracket, a spur gear on said staH meshing with said pinion, and a pinion on said latter staff adapted to transmit driving rotation to a spur gear on the drive statt' of said clock mechanism.

FREDERICK C. HOLTZ. 

